Mercury switch



May 8, 1934- G. F. CALLAHAN '1,957,591

MERCURY SWITCH ATTORN EY May 8, 1934.

G. F. CALLAHAN MERCURY SWITCH Filed Aug. 30, 1930 2 Sheets-Sheet 2 ATTORNE Patented May 8, 1934 UNITED STATES PATENT OFFICE MERCURY SWITCH Pennsylvania Application August 30, 1930, Serial No. 478,859

3 Claims.

The invention relates to automatic switch devices for intermittently operating electrical mechanism and relates more particularly to such devices in which a mercury pool is employed to make and break an electrical circuit.

An object of the present invention is to provide a simple and eiective intermittently operable device for making and breaking an electrical circuit.

Another object of the invention is to provide a device in which a mercury column and electrodes are given relative movement of making and breaking a circuit.

Another obiectof the invention is to provide an enclosed envelope having therein a mercury pool and column as a part of an electrical circuit, means operable within the envelope for automatically uniting and reuniting said pool and column to break and make said. circuit.

Another object of the invention is to provide a sealed envelope having therein a mercury column with movable elements for causing the column to bridge a pair of electrodes and external means for actuating the means within the envelopef Qther objects and advantages of the invention will be more fully understood together with the accompanying drawings in which,

Fig. l is a verticallsectional view of the device constructed in accordance with the present invention and showing an electrical diagram;

Fig. 2 is a view taken on lines II--II in Fig. l; Fig. 3 is a fragmentary enlargedsectional view of the device shown in Fig. 1 but with the operat- 3 ing elements in different positions;

Fig. 4 is a view taken on lines IV-IV in Fig. 3;

Fig. 5 is a fragmentary view showing an envelope and a modied form of circuit breaking mechanism and with a modified diagrammatic o electrical circuit;

Fig. 6 is a view similar to Fig. 5 but showing the internal operating elements in different positions;

Fig. 'l is a view taken on, lines VII-VII in Fig. e;

Fig. 8 is a vertical sectional view showing ancally operable switch mechanism which may be employed to intermittently make and break a circuit for various purposes. The selected embodiment of the invention, however, shows the same for operating one or more incandescent electric lamps intermittently as for example, when used in connection with sign or other lighting.

As shown in Fig. 1 a switch device indicated as a whole by the numeral 10 may comprise a glass envelope 1.1 having a press 12 through which electrodes 13 and 14 extend. The envelope may be provided with a column of mercury 15 and may be tipped oli at 16 in the usual manner.,

Ends 17 and 18 o1' the electrodes 13 and 14 respectively are secured in what may be termed a suspended or stationary chamber 19, the said chamber having a lateral inlet 2l and a stationary pool of mercury 22 which is permanently in contact with the electrode 14. Surrounding the chamber 19 is a hollowl iicat member 23 which may be of a material sufficiently light in Weight to be buoyant in the mercury column and which normally takes an upper position as shown in Fig. 1 so as to surround the chamber 19, which chamber actsas a plunger to enter the hollow oat and displace mercury therefrom in a manner to be presently described. 80

The chamber 19 is supported by the electrodes but the electrode 13 is inclosed in a wall of the chamber which is of insulating material thus the electrodes are normally electrically disconnected.

When the float is in its lower position. it will displace the mercury at the bottom of the envelope l1 causing the mercury to fio'w through inlet 21 and 23 thereby connecting the main or movable mercury pool 15 with the stationary mercury pool 22 ,which is in contact with the electrode 14, thus providing electrical contact between the main mercury pool 15 and the electrode 14. The end 17 of the electrode 13 is provided with a contact member 24 which extends from the bottom of the chamber 19 into contact with the mercury pool l5 thus completing the electrical circuit between the two electrodes when the said float is in its lower position, a downward movement of the float being caused by means to be presently described.

Means for causing a downward movement of the iloat 23 may comprise an electrical winding 25 disposed around the lower end of the envelope l1. One end of this winding or coil is connected to a conductor 26 leading to one side of a suitable source of electrical energy (not shown), the opposite end of the coil is connected by a conductor 27 leading to one side of mechanism to be operated, in the present case such mechanism being an incandescent electric lamp 28. The said conductor 27 connects with one side of the lament 29 of the lamp and the opposite side of the lamp is connected by conductor 31 which leads to the said source of electrical energy.

Lead wires 32 and 33 or the electrodes 13 and 14 respectively are provided with conductors 34 and 35. The conductor 35 is connected with the conductor 27 and the conductor 34 is connected with the conductor 26.

When current is caused to now in the conductors 26 and 31 a eld' is'created in the coil 25 and the float which may lbe oi iron or other magnetic metal acts as an armature of a solenoid. When current iiows through the coil which may be of high impedance, the lamp 28 which is in series with the coil does not light.

As the float 23 is moved downwardly, however, by reason of the effect of the coil, the mercury is forced through the inlet 21 in the stationary chamber 19 so that the main body of mercury 15 and the stationary body of mercury 22 unite, thus providing electrical connection between the electrodes 13 and 14 at which time a free current passage is aorded for the lamp 28 which is lighted and the coil 23 is short circuited permitting the float to rise and allowing the main body of mercury to fall.

By reason of a compensating hole 23 in the bottom of the float 23 the main body of mercury falls to a level below the inlet 21 thus breaking the electrical connection between the electrodes 13 and 14 and permitting current again to pass through the coil so that the above described operation is repeated.

In Figs. 5, 6 and 7 a construction is shown which maybe operated in substantially the same manner as the construction shown in Fig. 1, but the formation of the internal operating elements is somewhat modified. Referring to Fig. 5 specifically, the construction shown includes a glass envelope 36 having electrodes 37 and 38 extending therein. The lower ends of the electrodes are provided with a retainer-member 39 having a cavity 41 to receive a pool of mercury. A lower end 42 of the electrode 37 extends into the cavity 41 while a lower end 43 of the electrode 38 eX- tends through the member 39 and is provided with a lower contact member 44 which makes contact with a main body oi mercury 45.

Surrounding the electrodes 37 and 38 and the member 39 is a oat 46 in the form of a tubular chamber having an outlet opening 47 at the lower end thereof. When the float is in its upper position the main body of mercury is united with a mercury pool 48 in the cavity 41. A coil 49 surrounds the lower portion of the bulb 36 and the mercury 45 therein. One end of the coil 49 is connected by a conductor 51 which conductor connects with a suitable source of electrical energy supply (not shown).

An opposite end of the coil 49 is connected by a conductor 52 with the electrode 37 and the electrode 38 is connected with a conductor 53 leading to the aforementioned electrical energy supply. An incandescent lamp 54 may be connected between the conductors 51 and 52 so that when electrical energy flows through the conductor 53, electrode 38, main mercury pool 45, electrode 37 and conductor 52, through the coil 49 and through conductor 51 so that a field is set up within the coil and the oat is pulled downwardly. the coil, however, the lamp 54, which is in parallel with the coil circuit, is lighted. As the float moves downwardly the main body of mercury is carried away from the member 39 thus break- While current is iiowing through ing the connection between the stationary mercury pool 48 and the main body of mercury 45. When the float is in this position the mercury which has surrounded the member 39 is carried away from the said member and inasmuch as the electrical connection is broken between electrodes 37 and 38 no current will now through the circuit and the lamp 54 will not be lighted. Obviously no current will be flowing through the con 49 so that no force will be exerted to hold the oat 46 in its lower position.

rhe float will, therefore, by reason of its buoyancy rise to the position shown in Fig. 5 carrying with it an amount of mercury sufiicient to immerse the member 39 and unite the stationary pool of mercury with the main body of mercury causing the lamp to light and the coil to be energized for a repetition of the afore-described operations.

In Figs. 8, 9 and 10 a device of the same general character as already described is shown except that the movable member instead of being a float is sufficiently weighted so that its downward movement is due to its potential energy.- As illustrated such a construction may include a glass envelope 55 containing a mercury column 56. Electrodes 57 and 58 are sealed in a press 59 at one end of the envelope. An external. end 61 of electrode 57 is provided with a conductor 62 connected to one end of a coil 63 which surrounds a portion of the envelope 55. The opposite end of the said coil is connected by a conductor 64 leading to a suitable source of electrical energy supply (not shown). The external end 65 of the electrode 58 is provided with a conductor 66 which leads to the said electrical energy source. The mercury column 56 occupies an appreciable portion of the lower end of the envelope 55 and a movable element 67 which may be termed a weighted chamber is disposed within the envelope 55 and normally takes a lower position so as to be partially submerged in the mercury column as shown in Fig. 8.

The movable element 67 is provided with a passageway 68 to receive the electrode 58, the lower end 69 of which projects from the movable element 67 and makes contact with the mercury column 56. The element 67 is provided with a chamber 71 having an insulative lining 72 and an end 73 of the electrode 57 projects into the said chamber.

When the element 67 is in its lower position mercury flows through an inlet aperture 74 filling the lower portion of the chamber 71 and providing a movable pool of mercury 75 in which the end 73 of the electrode 57 is immersed. When the element 67 is in its lower position the main body of mercury 56 and the movable body of mercury 75 are united thus electrical connection is completed between the electrodes 57 and 58 since both electrodes are in contact with the united bodies of mercury. Electrical energy will then ow through conductor 66, electrode 58, united bodies of mercury 56 and 75, electrode 57, conductor 62, coil 63 and conductor 64; thus the coil 63 will be energized and the element 67 Which may be of iron or suitable magnetic material will act as an armature and move upwardly. At this time mechanism to be intermittently operated, as for example, an incandescent electric lamp 76,

will be lighted since the lamp 76 is connected by means of `conductors 77 and 78 to conductors 62 and 64 respectively. t

When the element 67 is raised, as shown in Fig. 9, the movable pool of mercury 75 will be removed from the main pool of mercury 56 and the electrical connection between the electrodes 57 and 58 will be broken at which time the lamp 76 will be inoperative and obviously no electrical energy will flow through the coil 63.

The element 67 will then be free to drop under the force of gravity and again take the position as shown in Fig. 8 so that the movable body of mercury will be again united with the mercury column 56 and the coil 63 energized and the lamp again lighted.

By reason of the present invention an automatically operable mercury switch device may be produced at relatively low cost.

By reason of theV simplicity of construction the device is operable over long time periods without attention as is necessary with certain other devices where wearing parts are necessary, and since durability is essential in devices of the present character particularly in sign lighting, the present invention is of great advantage.

It will also be appreciated that owing to the present novel form of construction the make and break of the circuit is accomplished by the relative movement of vtwo bodies of mercury and that any arc which occurs will break over a highly insulative or refractory member thus avoiding detrimental eiects on the glass of the enclosing envelope.

Although a preferred embodiment of the invention is shown and described herein it is to be understood that modications may be made therein without departing from the spirit and scope of the invention as set forth in the appended claims.

What is claimed is:

l. A mercury switch comprising an envelope, a mercury column in said envelope, a pair of electrodes extending through a wall of said envelope, a stationary chamber Within said envelope, a mercury pool in said chamber, one of said electrodes extending into said pool and the other electrode in contact with said mercury column, a tubular movable member, and electro-magnetic means for moving said movable member along said stationary chamber to displace mercury in said column and unite said column with said pool.

2. A mercury switch comprising an envelope, a mercury column in said envelope, a pair of electrodes extending through a wall of said en-y velope, a chamber suspended on said electrode, a mercury pool in said chamber and in contact with one of said electrodes, the other ol said electrodes extending through a wall of said chamber and having a portion in contact with said mer cury column and means movable into said merma cury column to displace and unite the same with said pool.

3. A mercury switch comprising an envelope, a pair of electrodes extending through a wall at one end of said envelope, a mercury column at the other end of said envelope, a chamber containing a mercury pool suspended in said envelope and surrounded by said mercury, a float movable along said chamber and in said mercury column, an end of one of said electrodes being in Contact with said mercury column, the other electrode end being disposed in said chamber, means for reciprocating said float to displace the mercury of said column and unite it with said pool to connect said electrodes and to separate said column and pool to disconnect said electrodes.

GEORGE F. CALLAHAN. 

